It is no easy job to carry out a general plan for birth control throughout the world becau

It is no easy job to carry out a general plan for birth control throughout the world because__________ ．

A.there are too many underdeveloped countries in the world

B.underdeveloped countries have low level of industrial development

C.different governments have different views about the problem

D.even developed countries may have complex problems

请帮忙给出正确答案和分析，谢谢！